Electrolysis Cleaning for Iron Relics: Step-by-Step
Electrolysis uses a low-voltage electrical current to reduce iron oxide (rust) back to a more stable form and to loosen encrusted soil from iron artifacts. It's the standard conservation method for dug iron and produces excellent results when done correctly.
What You Need
- A plastic container (bucket, storage tub — not metal)
- A battery charger or DC power supply (12V, 2-10 amps)
- Washing soda (sodium carbonate, sold as "Arm & Hammer Super Washing Soda")
- A sacrificial anode (scrap steel or iron — not stainless steel, which releases toxic hexavalent chromium)
- Wire leads with alligator clips
- Water
Setup
- Fill the container with water and dissolve washing soda at roughly 1 tablespoon per gallon.
- Connect the negative (black) lead from the charger to the artifact. This is critical — the artifact must be on the negative terminal.
- Connect the positive (red) lead to the sacrificial anode.
- Submerge both in the solution, keeping them from touching each other.
- Turn on the charger. You should see bubbles forming on the artifact within seconds.
Process
Leave the artifact in the solution for hours to days depending on size and corrosion severity. Check periodically and brush off loosened material with a nylon brush. The sacrificial anode will corrode — that's normal and expected. Replace it when it gets thin. Change the water when it gets dark and murky.
After Electrolysis
Remove the artifact and scrub off remaining loose material with a nylon or brass brush under running water. The iron will be clean but completely unprotected and will begin rusting immediately. You must seal it promptly with one of these methods:
- Paste wax: Renaissance Wax is the museum standard. Warm the artifact slightly for better penetration.
- Boiled linseed oil: Traditional and effective. Apply thin coats and let cure.
- Clear lacquer: Quick and durable but harder to reverse if needed later.